Plastic tanked heat exchanger-side, header tank assembly

ABSTRACT

A tank to header attachment construction for heat exchangers include T-shaped tabs on the header which extend through slots in a flange on a tank. The top bar of each tab has it ends bent out of alignment with the slot to secure the tank to the header.

FIELD OF THE INVENTION

This invention relates to heat exchangers of the type having a headerreceiving the open ends of a plurality of tubes and a tank and/or sidepiece secured to the header; and more particularly, to an improvedattachment of the tank and/or side piece to the header for brazing.

BACKGROUND OF THE INVENTION

Heat exchangers commonly have a plurality of parallel flat sidedextruded or roll formed tubes connected at opposite ends to a pair ofheader-tank assemblies, and a plurality of fins between and bonded tothe tubes to facilitate efficient heat transfer to the surrounding area.Each header-tank assembly generally comprises a header with slotstherethrough for receiving the tubes, and a tank secured to the headerto contain a heat exchange fluid medium and receive the same from thetubes. The fins are brazed or soldered to the sides of adjacent tubes,and the tubes are brazed or otherwise bonded to the header along withthe tank to assure leak free joints.

During assembly, the header and tank must be secured to one another toseal the joint therebetween. Tabs of various sorts are known for tankretention of headers. For example, T-shaped tabs located on the headerare employed in Buchanan U.S. Pat. No. 5,195,579. In this patent, theso-called bars or tops of the T-shaped tabs are bent inwardly in theirentirety over a flange on the tank so as to hold the header and tankassembly together. While such known connections between the tank and theheader may perform acceptably for their intended purpose, there isalways room for improvement. For example, there is a continuing desireto make the connection easier to form and to improve pressureresistance. In addition, there is a need for an improved means ofattaching side pieces to the headers.

SUMMARY OF THE INVENTION

It is the principal object of the invention to provide a new andimproved means of assembling a header and tank and/or a side piece witha header in a heat exchanger, and more specifically, to provide animproved means to lock the side piece and/or the header to assure brazejoint and maintain header to header dimension during brazing.

According to one aspect of the invention, a heat exchanger comprises atank, a header and a plurality of tubes. The tank has a flange thatextends around a periphery of an open end of the tank. The flange has aplurality of spaced openings. The header receives open ends of thetubes. A plurality of tabs extend from an outer periphery of the header.The tabs pass through the openings and are bent to a position overlyingthe flange to prevent removal of the tank from the header. The tabs areT-shaped. Each of the T-shaped tabs has an upright part extending fromthe outer periphery of the header and a top bar connected with theupright part. With the T-shaped tabs passing through the openings in thetank, the top bars are bent to a position overlying the flang of thetank to prevent removal of the tank from the header.

In a preferred embodiment, only the ends of the top bars are bent tooverly the flange.

According to another aspect of the invention, the heat exchanger furthercomprises a side piece. The side piece includes a tab extending from itsends. Each tab has an aperture. The header has a slot at a side of theheader and includes a deformable tab extending from the header. With thetab of the side piece located in the slot, the deformable tab isdeformed into the aperture to lock the side piece to the header. In oneform, the tab of the side piece is T-shaped. The T-shaped tab passesthrough the corresponding opening in the tank and is bent to overlie theflange to secure the tank to the side piece.

Other objects and advantages will become apparent from the followingspecification taken in connection with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a fragmentary perspective view of a heat exchanger including aheader-tank assembly and a pair of side pieces in accordance with oneembodiment of the invention;

FIG. 2 is a perspective view of a tank of the header-tank assembly ofFIG. 1;

FIG. 3 is a fragmentary partial sectional view of the heat exchanger ofFIG. 1;

FIG. 4 is a perspective view of the side piece attached to the header ofFIG. 1; and

FIG. 5 is a plan view of the header of FIG. 1.

DESCRIPTION OF THE PREFERRED EMBODIMENT

For the purpose of promoting an understanding of the principles of theinvention, reference will now be made to the embodiment illustrated inthe drawings and specific language will be used to describe the same. Itwill nevertheless be understood that no limitation of the scope of theinvention is thereby intended, such alterations and furthermodifications in the illustrated device, and such further application ofthe principles of the invention as illustrated therein beingcontemplated as would normally occur to one skilled in the art to whichthe invention relates.

FIG. 1 is a fragmentary perspective view of a heat exchanger 10. Theheat exchanger 10 comprises a pair of header-tank assemblies 12, onlyone of which is shown. The header-tank assemblies 12 support a core 14therebetween. The core 14 includes a plurality of flat sided tubes 16formed by extrusion, roll forming or the like and of a heat exchangefluid medium arranged in parallel relationship for providing parallelflow. A plurality of fins 18 are arranged between the tubes 16 forthermal coupling of the tubes 16 with ambient air.

The header-tank assembly 12 is formed by a header 20 and a tank 22. Theheader 20 includes a plate 24 having a plurality of slots 26, as bestseen in FIGS. 4 and 5, for receiving the open ends of the tubes 16 whichare in turn bonded thereto. The tank 22 includes a cover side 30 and anopposite open end 32. Assembly of the tank 22 onto the header 20 resultsin formation of a flow channel 34 (see FIG. 3). A heat exchange fluidmedium to be heated or cooled flows into or out of the flow channel 34through the tubes 16. The tank 22 may also include one or more circularports 36 in fluid communication with the flow channel 34 for flowing themedium into or out of the flow channel 34.

Referring to FIG. 2, the tank 22 also includes a flange 38 that extendsaround the periphery of the open end of the tank 22 and extendsoutwardly therefrom and extends outwardly therefrom. The flange 38 has aplurality of spaced openings 46 about the periphery of the tank 22 andtwo centered openings 46′ (only one shown in FIG. 2) at two sides of thetank 22 respectively. Preferably, the openings 46 and 46′ arerectangular. The flange 38 includes an upper surface 40 and a bottomsurface 42 that is useful for sealing against a peripheral seal 44 asshown in FIG. 3. The seal is placed within the header 20 prior to thecoupling of the tank 22 to the header 20. The seal 44 is preferably ano-ring. The seal 44 is located just within an upstanding flange 45 thatextends peripheral about the header plate 24. The seal 44 may be of anyform known to those of ordinary skill in the art. Referring to FIG. 2,the tank 22 also includes a plurality of ribs 48 spaced relatively flatparts of the exterior surface of the cover 30 and extend to the uppersurface 40 of the flange 38. The ribs 48 stiffen the cover 30 so as toresist the pressure within the flow channel 34 allowing a relativelythin cover. However, those of ordinary skill in the art will recognizethat by thickening the cover 30 or substituting a high strength materialfor the manufacture of the tank 22, it is not necessary to have theribs. The tank 22 is typically made from a heat resistant structuralplastic.

With respect to FIG. 4, the header plate 24 is surrounded by aperipheral flange 45 as mentioned previously. A plurality of tabs 54project upward from the flange 45 and extend generally around theperiphery of the header 20. The tabs 54 are T-shaped. Each of theT-shaped tabs 54 has an upright part 56 extending from the peripheraledge wall 50 of the header 20 and a top bar 58 connected with theupright part 56 at its midpoint. The T-shaped tabs 54 pass through theopenings 46 and 46′ in the tank 22 and the ends 59 of the top bars 58are deformed to either side of the upright part 56 of generally towardor away from the tank 22 to overlie the upper surface 40 of the tankflange 38 to assemble of the tank 22 to the header 20. The deformed tabsare indicated with 54′ as shown in FIGS. 1 and 3.

In the usual case, the tank 22 is fitted to the header with the seal 44in place. The tank and header are moved together to compress the seal 44and to cause the top bars 58 to clear the upper surface 40 of the flange38 and compress the seal 44. The top bars 58 are then deformed, leavingthe seal 44 in compression, or at least an contact with both the headerplate 24 and tank flange 38. The header 20 is preferably fabricated froma brazeable material, such as by way of example only, aluminum.

In one embodiment, the heat exchanger 10 also includes a pair of sidepieces 60 secured to the header 20 and the tank 22 as shown in FIG. 1 toprotect the fins 18 on the end most tubes 18 and/or assist in holdingvarious components together during assembly. With respect to FIG. 3, atab 62 extends from each end (only one shown) of the side piece 60.There is an aperture 64 at the bottom of the tab 62. Preferably, the tab62 is T-shaped. The side pieces 60 are typically made from aluminum. Asbest seen in FIG. 5, the peripheral flange 45 of the header 20 furtherincludes a pair of slots 66 at two sides of the header 20 respectively.Referring to FIG. 4, a pair of deformable tabs 68 extend from theperipheral flange 50 of the header 20 proximate to the slots 66. Withthe side piece tab 62 located in the corresponding slot 66, thedeformable tab 68 of the header 20 is deformed into the aperture 64 ofthe side piece tab 62 to lock the side piece 60 to the header 20. Thetab of the header at 68′ in its deformed state is indicated with 68′ asshown in FIGS. 4 and 5. With the T-shaped tab 62 of the side piecepassing through the corresponding opening 46′ in the tank 22 as shown inFIG. 1, the top bar of T-shaped tab 62 of the side piece 60 is bent tooverlie the upper surface 40 of the tank flange 38 (not shown) as statedabove.

From the foregoing, it will be appreciated that the header 20 may beattached to the tank 22, for example, by means of the T-shaped taps 54of the header 20 passing through the openings 46 and 46′ in the tankflange 38 and bent to overlie the tank flange 38.

It should be appreciated that the side piece 60 can be attached to theheader 20, for example, by means of the deformable tab 68 of the header20 inserted into the aperture 64 of the side piece tab 62.

It should also be appreciated that the side piece 60 can be attached tothe tank 22, for example, by means of the T-shaped side piece tab 62passing through the corresponding opening 46′ in the tank 22 and bent tooverlie the tank flange 38.

1. A heat exchanger having a plurality of tubes, each of the tubeshaving an open end, the heat exchanger comprising: a tank having aflange that extends around an periphery of an open end of the tank, theflange having a plurality of spaced openings; and a header supportingthe open ends of the tubes and including a plurality of tabs extendingfrom an outer periphery of the header, the tabs passing through theopenings and bent to a position overlying the flange to prevent removalof the tank from the header; wherein the tabs are T-shaped, each of theT-shaped tabs has an upright part extending from the outer periphery ofthe header and a top bar connected with the upright part, the openingsin the tank sized to allow passage of the top bars therethrough, withthe T-shaped tabs passing through the openings in the tank, the top barsare bent to a position overlying the flange of the tank to preventremoval of the tank from the header.
 2. A heat exchanger having aplurality of tubes, each of the tubes having an open end, the heatexchanger comprising: a tank having a flange that extends around anperiphery of an open end of the tank, the flange having a plurality ofspaced openings; a header supporting the open ends of the tubes andincluding a plurality of first tabs extending from an outer periphery ofthe header, the first tabs passing through the openings and bent to aposition overlying the flange to prevent removal of the tank from theheader; and a side piece, the side piece including a second tabextending from the side piece and having an aperture; wherein the headerhas a slot at a side of the header and includes a deformable third tabextending from the header, with the second tab of the side piece locatedin the slot, the deformable third tab is deformed into the aperture tolock the side piece to the header.
 3. The heat exchanger of claim 2wherein the second tab of the side piece is T-shaped, the T-shapedsecond tab has an upright part extending from the side piece and a topbar connected with the upright part, with the T-shaped second tabpassing through the corresponding opening in the tank, the top bar isbent to a position overlying the flange of the tank to prevent removalof the tank from the side piece.
 4. The heat exchanger of claim 3wherein said top bar has ends which are bent to a position overlying theflange of the tank.
 5. A heat exchanger having a plurality of tubes,each of the tubes having an open end, the heat exchanger comprising: atank having a flange extending from an outer periphery of the tank, theflange having a plurality of spaced openings; a header receiving theopen ends of the tubes, the header having a slot, the header furtherincluding a plurality of T-shaped tabs extending from an outer peripheryof the header and passing through the openings in the tank, each of theT-shaped tabs has an upright part extending from the outer periphery ofthe header and a top bar connected with the upright part, with theT-shaped tab passing through the openings, the top bars are bent to aposition overlying the flange of the tank to prevent removal of the tankfrom the header; and a deformable tab extending from the outer peripheryof the header; a side piece including a T-shaped tab extending from theside piece, the T-shaped tab of the side piece having an aperture, theT-shaped tab of the side piece having an upright part extending from theside piece and a top bar connected with the upright part, with theT-shaped tab of the side piece located in the slot and passing throughthe corresponding opening in the tank, the deformable tab of the headeris deformed into the aperture to lock the side piece to the header andthe top bar is bent to a position overlying the flange of the tank toprevent removal of the tank.